This core is designed to meet the needs of all four research projects on this Program Project Grant. The core personnel consist of the Core Director, one full-time Technician and one half-time Research Technician. The I core has two components. One will be to provide chimerism analyses in dogs (Projects 1 and 2) and human patients (Projects 3 and 4) after nonmyeloablative conditioning and hematopoietic cell transplantation. These analyses will be performed using polymerase chain reaction (PCR)-based microsatellite marker polymorphism assays. These studies will serve to monitor the degree of donor engraftment in all four research projects. The second goal will be to provide canine histocompatibility typing for Projects 1 and 2 with the aim of selecting dog leukocyte antigen (DLA) identical littermate donor-recipient pairs for transplantation.